JPH0217203Y2 - - Google Patents

Description

【考案の詳細な説明】 本考案は定速で作動する多段形複動油圧シリン
ダ装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-stage double-acting hydraulic cylinder device that operates at a constant speed.

複数の可動シリンダがテレスコープ式に往復動
する多段形複動油圧シリンダは、長いストローク
を必要としながら取付スペースに制約がある場合
に頻繁に用いられる。しかしこの種シリンダにお
いては、往動時または復動時の各作動中に複数の
可動シリンダが順次作動するため速度が一定せ
ず、したがつて作動する可動シリンダの切替わり
時にシリンダ及び負荷に衝撃が発生するため用途
に限界があつた。 Multi-stage double-acting hydraulic cylinders in which a plurality of movable cylinders reciprocate in a telescopic manner are frequently used when a long stroke is required and installation space is limited. However, in this type of cylinder, the speed is not constant because multiple movable cylinders operate sequentially during each forward or backward motion, and therefore, when the movable cylinder is switched, an impact is applied to the cylinder and the load. There are limits to its usage due to the occurrence of

本出願人は、上述の問題を解決するために、先
に特開昭59−80513号に記載の装置を提案した。
この装置は簡単な構成にもかかわらずほぼ一定の
速度で作動するという優れたものである。しか
し、この装置においては、多段形複動式油圧シリ
ンダ特有の構造から、各可動シリンダにおける往
動側油室の有効断面積が通常復動側油室のそれの
1.5〜４倍程度となる。したがつて各可動シリン
ダの往復動に同じ油圧力を使用した場合、往動時
には往動側油室に大流量が流れるが、復動時に
は、復動側油室に流れる流量が往動側油室よりも
上記の逆倍率で１／1.5〜１／４程度少なくなつ
て復動方向への出力が小さくなるうえ、大流量が
流れる往動側油室に背圧が発生するためその復動
方向の出力は一層減少し、しかしてこのような復
動時における出力不足から、負荷の大きさによつ
ては復動時の作動速度が低下して往動時の作動速
度と等速にはならない場合が生じるいう問題があ
つた。 In order to solve the above-mentioned problem, the present applicant previously proposed a device described in Japanese Patent Application Laid-open No. 80513/1983.
This device is excellent in that it operates at a nearly constant speed despite its simple construction. However, in this device, due to the unique structure of multi-stage double-acting hydraulic cylinders, the effective cross-sectional area of the forward-acting oil chamber in each movable cylinder is usually larger than that of the backward-acting oil chamber.
It will be about 1.5 to 4 times. Therefore, if the same hydraulic pressure is used for the reciprocating motion of each movable cylinder, a large amount of flow will flow into the forward side oil chamber during forward movement, but during backward movement, the flow flowing into the backward movement side oil chamber will be smaller than the amount flowing into the forward side oil chamber. The above reverse magnification is about 1/1.5 to 1/4 smaller than in the chamber, so the output in the backward direction is smaller, and back pressure is generated in the forward side oil chamber, where a large flow flows, so the output in the backward direction is reduced. The output of the motor decreases further, and due to this lack of output during the backward movement, the operating speed during the backward movement may decrease depending on the load size and may not reach the same speed as the operating speed during the forward movement. There was a problem that some cases may occur.

本考案は上述の点に鑑みてなされたもので、簡
単な構成を追加することによつて復動方向の出力
低下を防止し、ほぼ一定の速度で作動する多段形
複動油圧シリンダ装置を提供するものである。 The present invention was developed in view of the above points, and provides a multi-stage double-acting hydraulic cylinder device that prevents a decrease in output in the backward-acting direction by adding a simple configuration and operates at a nearly constant speed. It is something to do.

以下本考案の実施例を説明すると、第１図はこ
の考案に使用する多段形油圧シリンダの実施例で
あつて、基本シリンダ１内に、ピストン２，３を
それぞれ基端部側に有する可動シリンダ４，５を
順次嵌装し、第１可動シリンダ４のピストン２に
その軸方向に流通路６を設けて各可動シリンダ
４，５の往動側油室７，８を相互に連通させ、一
方同じく第１可動シリンダ４のピストン２の中央
に軸方向に延びる送通管９を突設し、ピストン２
の半径方向には、流通路１０を設け、また第２可
動シリンダ５のチユーブ５ａにはピストン３との
接続部付近においてチユーブ５ａ内外を連通する
複数の流通孔１１ａ，１１ｂ，１１ｃを設けて各
可動シリンダ４，５の復動側油室１２，１３を相
互に連通させてある。 An embodiment of the present invention will be described below. Fig. 1 shows an embodiment of a multi-stage hydraulic cylinder used in this invention, which is a movable cylinder having pistons 2 and 3 on the base end side in a basic cylinder 1. 4 and 5 are fitted one after another, a flow passage 6 is provided in the piston 2 of the first movable cylinder 4 in its axial direction, and the forward oil chambers 7 and 8 of each movable cylinder 4 and 5 are communicated with each other. Similarly, a delivery pipe 9 extending in the axial direction is provided protrudingly from the center of the piston 2 of the first movable cylinder 4, and the piston 2
A flow path 10 is provided in the radial direction of the tube 5a of the second movable cylinder 5, and a plurality of flow holes 11a, 11b, 11c are provided in the tube 5a of the second movable cylinder 5 in the vicinity of the connection with the piston 3 to communicate between the inside and outside of the tube 5a. The reciprocating side oil chambers 12 and 13 of the movable cylinders 4 and 5 are communicated with each other.

ここにおいて、第１可動シリンダ４のピストン
２には、その半径方向に設けた流通路１０の外周
への開口部分に対応して円環状の凹溝１４を設け
てあり、この凹溝１４と復動側油室１２とを連通
する絞り孔１５をピストン２に１箇所または複数
箇所設けてある。一方基本シリンダ１のチユーブ
１ａの両端部には肉厚部１ｂを形成してあり、両
肉厚部１ｂには２個のヘツド側給排ポート１６，
１６及びロツド側給排ポート１７が設けてある。
このロツド側給排ポート１７は、復動側油室１２
内へロツド側端より若干ヘツド側寄り位置に開口
しており、第１可動シリンダ４がロツド側すなわ
ち図の上方へ移動した場合において、ピストン２
がロツド側端へ当接する若干手前でクツシヨン作
用が行われるとともに、第２可動シリンダ５への
流路の切替えが行われる。 Here, the piston 2 of the first movable cylinder 4 is provided with an annular groove 14 corresponding to the opening to the outer periphery of the flow passage 10 provided in the radial direction. The piston 2 is provided with one or more throttle holes 15 that communicate with the moving side oil chamber 12 . On the other hand, thick wall portions 1b are formed at both ends of the tube 1a of the basic cylinder 1, and two head side supply/discharge ports 16,
16 and a rod side supply/discharge port 17 are provided.
This rod side supply/discharge port 17 is connected to the double-acting side oil chamber 12.
It opens inward at a position slightly closer to the head side than the rod side end, and when the first movable cylinder 4 moves toward the rod side, that is, upward in the figure, the piston 2
A cushioning action is performed slightly before the rod comes into contact with the rod side end, and the flow path to the second movable cylinder 5 is switched.

また、第２可動シリンダ５のチユーブ５ａに設
けた流通孔１１ａ，１１ｂ，１１ｃは、軸方向に
複数個併設されており、ピストン側から順次径大
となつている。したがつて第２可動シリンダ５が
往動してピストン３がロツド側端に達する若干手
前において流通孔１１ａ，１１ｂ，１１ｃが径大
のものから順次ロツドカバー４ａに嵌入して閉塞
され、復動側油室１３の排出流路が絞られてクツ
シヨン効果が得られる。 Further, a plurality of communication holes 11a, 11b, and 11c provided in the tube 5a of the second movable cylinder 5 are arranged side by side in the axial direction, and the diameters become larger sequentially from the piston side. Therefore, slightly before the second movable cylinder 5 moves forward and the piston 3 reaches the rod side end, the communication holes 11a, 11b, and 11c are fitted into the rod cover 4a in order from the largest diameter to be closed, and the second movable cylinder 5 moves forward and is closed by the rod cover 4a. The discharge flow path of the oil chamber 13 is constricted to provide a cushioning effect.

さて、第１可動シリンダ４のピストン２には、
往動側油室７に面する側中央にクツシヨンボス１
８を形成し、ヘツドカバー１ｄにはクツシヨンボ
ス１８と微少間隙を有して嵌合するクツシヨン穴
１９を設けてある。クツシヨンボス１８は円柱状
物の端面中央に凹所１８ａを有しかつピストン２
との接続部分が径小となつた形状で、このクツシ
ヨンボス８の軸方向長さはクツシヨン穴１０の深
さよりも長くしてあり、さらに凹所１８ａから外
周方向へ貫通する貫通孔１８ｂと、貫通孔１８ｂ
と往動側油室７とに貫通する径小の絞り孔１８ｃ
とを有している。したがつてピストン２が復動し
てクツシヨンボス１８がクツシヨン穴１９へ嵌入
すると、クツシヨン穴１９内の流体は絞り孔１８
ｃによつて排出流路が絞られてクツシヨン効果が
得られるとともにクツシヨンボス１８先端がクツ
シヨン穴１９の底部に当接してストツパの作用を
なす。 Now, in the piston 2 of the first movable cylinder 4,
A cushion boss 1 is located in the center of the side facing the forward oil chamber 7.
8, and the head cover 1d is provided with a cushion hole 19 which fits into the cushion boss 18 with a slight gap therebetween. The cushion boss 18 has a recess 18a in the center of the end surface of the cylindrical member, and
The axial length of the cushion boss 8 is longer than the depth of the cushion hole 10, and the through hole 18b extends from the recess 18a toward the outer circumference. Hole 18b
and a small-diameter throttle hole 18c that penetrates the forward oil chamber 7.
It has Therefore, when the piston 2 moves back and the cushion boss 18 fits into the cushion hole 19, the fluid in the cushion hole 19 flows through the throttle hole 18.
c narrows the discharge flow path to obtain a cushion effect, and the tip of the cushion boss 18 comes into contact with the bottom of the cushion hole 19 to act as a stopper.

第１可動シリンダ４のピストン２と基本シリン
ダ１のヘツドカバー１ｄとの間に形成した上述の
クツシヨン装置と同様のものを、第２可動シリン
ダ５のピストン３と第１可動シリンダ４のピスト
ン２との間に形成してある。ただし、ピストン２
には円管状の送通管９を突設しこの送通管９がピ
ストン３を貫通しているので、ピストン３には円
環状のクツシヨンボス２０を、またピストン２に
はこれに嵌合するクツシヨン穴２１を形成してあ
り、クツシヨンボス２０には径小の絞り孔２０ａ
を設けてある。 A cushion device similar to the above-described cushion device formed between the piston 2 of the first movable cylinder 4 and the head cover 1d of the basic cylinder 1 is connected to the piston 3 of the second movable cylinder 5 and the piston 2 of the first movable cylinder 4. It is formed in between. However, piston 2
A circular passage tube 9 is provided protruding from the piston 3, and this passage tube 9 passes through the piston 3. Therefore, the piston 3 is provided with a circular cushion boss 20, and the piston 2 is provided with a cushion that fits therein. A hole 21 is formed in the cushion boss 20, and a small diameter aperture hole 20a is formed in the cushion boss 20.
is provided.

ところで、各可動シリンダ４，５の復動側油室
の面積及び送通管９の面積を考慮することによつ
て、各復動側有効断面積を同一にすることができ
る。しかし現実には材料寸法または加工誤差等の
関係から全く同一にすることは困難であり、また
その必要もなく、通常数パーセント乃至十数パー
セントの面積の差異は許容されるであろう。 By the way, by considering the area of the reciprocating side oil chamber of each movable cylinder 4, 5 and the area of the passage pipe 9, the effective cross-sectional area of each reciprocating side can be made the same. However, in reality, it is difficult to make them exactly the same due to material dimensions, processing errors, etc., and it is not necessary, and a difference in area of several percent to ten-odd percent is usually acceptable.

次に油圧回路について説明すると第２図におい
て、多段形複動油圧シリンダ２２の往動側油室
７，８に通じる一方のヘツド側給排ポート１６、
及び復動側油室１２，１３に通じるロツド側給排
ポート１７は、それぞれ方向切換弁２３に接続し
てあり、かつロツド側給排ポート１７と方向切換
弁２３との間には、二個の圧力補償付流量制御弁
２４ａ，２４ｂを互いに逆方向に直列接続したも
のを介在させている。この圧力補償付流量制御弁
２４ａ，２４ｂは、回路圧力が変化してもほぼ一
定の流量を保つもので、外部からその流量を調整
できるようになつている。また逆止弁を内蔵して
おり、一方向へは自由流となる。したがつてこれ
ら二個を互いに逆方向に直列接続することによつ
て、正逆各流れ方向の流量をそれぞれ別個に調整
することができる。 Next, to explain the hydraulic circuit, in FIG.
The rod side supply and discharge ports 17 that communicate with the reciprocating side oil chambers 12 and 13 are each connected to the directional switching valve 23, and there are two ports between the rod side supply and discharge port 17 and the directional switching valve 23. A pressure-compensated flow control valve 24a, 24b connected in series in opposite directions is interposed. The pressure-compensated flow rate control valves 24a and 24b maintain a substantially constant flow rate even if the circuit pressure changes, and can adjust the flow rate from the outside. It also has a built-in check valve, allowing free flow in one direction. Therefore, by connecting these two in series in opposite directions, the flow rates in the forward and reverse flow directions can be adjusted separately.

また方向切換弁２３には、減圧弁２５を介して
油圧ポンプ２６を、逆止弁２７を介して油タンク
２８を、それぞれ接続してある。減圧弁２５は、
ヘツド側給排ポート１６に供給する圧力を制限す
るものであり、また逆止弁２７は自由流れ方向の
クラツキング圧力を利用して一定の背圧を発生さ
せるためのものである。符号２９はリリーフ弁で
ある。他方のヘツド側給排ポート１６と油タンク
２８との間には、開閉弁３０を有した戻り流路３
１が形成されている。戻り流路３１は、油圧シリ
ンダ２２が復動する際に、往動側油室７，８内の
油をこの戻り流路３１を通して油タンク２８へ速
かに排出し、往動側油室７，８内に生じる背圧を
最小限におさえるためのものであつて、開閉弁３
０は油圧シリンダ２２が復動するときのみ開とな
るように制御されている。 Further, a hydraulic pump 26 and an oil tank 28 are connected to the directional switching valve 23 via a pressure reducing valve 25 and a check valve 27, respectively. The pressure reducing valve 25 is
The check valve 27 is used to limit the pressure supplied to the head side supply/discharge port 16, and the check valve 27 is used to generate a constant back pressure using cracking pressure in the free flow direction. Reference numeral 29 is a relief valve. A return passage 3 having an on-off valve 30 is provided between the other head-side supply/discharge port 16 and the oil tank 28.
1 is formed. The return flow path 31 quickly discharges the oil in the forward oil chambers 7 and 8 to the oil tank 28 through the return flow path 31 when the hydraulic cylinder 22 moves backward. , 8 to minimize the back pressure generated within the on-off valve 3.
0 is controlled to open only when the hydraulic cylinder 22 moves backward.

したがつて方向切換弁２３を切換えることによ
つて、各給排ポート１６，１７には選択的に油圧
源または油タンクが接続されるとともにその時の
流量は圧力補償付流量制御弁２４ａ，２４ｂによ
り制御され、常にほぼ一定の調整された流量が流
れる。そして、油圧シリンダ２２が復動するとき
には、開閉弁３０が開き、往動側油室７，８内の
油は両方のヘツド側給排ポート１６，１６から流
路２３ａ及び戻り流路３１を通つて背圧をほとん
ど発生することなく油タンク２８へ排出され、油
圧シリンダ２２の復動方向の出力の低下が防止さ
れる。 Therefore, by switching the directional switching valve 23, a hydraulic power source or an oil tank is selectively connected to each supply/discharge port 16, 17, and the flow rate at that time is controlled by the pressure compensated flow control valves 24a, 24b. A controlled and nearly constant regulated flow rate flows at all times. When the hydraulic cylinder 22 moves backward, the on-off valve 30 opens, and the oil in the forward oil chambers 7, 8 flows from both head side supply/discharge ports 16, 16 through the flow path 23a and the return flow path 31. As a result, the oil is discharged into the oil tank 28 without generating almost any back pressure, and a decrease in the output of the hydraulic cylinder 22 in the backward movement direction is prevented.

ここに用いた方向切換弁２３は、４ポート３位
置のものであるが、上述した機能を満たすもので
あればこれに限定されず、例えば５ポート３位置
のもの、４ポート２位置のものまたは３ポート２
位置を２個使用してもよい。開閉弁３０は２ポー
ト２位置のものを用いたが、３ポート又は４ポー
トのものでもよい。第２図に示す油圧回路は配管
によつて接続してもよいし、ベース用のマニホー
ルドに所要のモジユール弁を積み重ねることによ
つて実現してもよい。一般的に、モジユール弁を
積み重ねるにはこれらの全ての弁に同一の口径の
弁を使用しなければならないので、仮に開閉弁３
０を使用せず方向切換弁２３の口径を大きなもの
にして大流量に対応しようとすれば、他の全ての
弁も同様に口径の大きなものを使用しなければな
らず全体として非常に高価なものについてしま
う。したがつて本考案は、モジユール弁を使用す
る場合に特に効果があるといえる。また逆止弁２
７によつて一定の低い背圧が確実に発生するが、
これによつて多段形複動シリンダ２２の各可動シ
リンダ４，５の動作順序が確保される。すなわ
ち、第１可動シリンダ４のピストン２と第２可動
シリンダ５のピストン３とが軸方向に離間した状
態にあるときには第１可動シリンダ４は、その復
動側油室１２，１３の圧力がそれぞれ逆方向に働
いてバランスするので往動側油室７に圧力があれ
ばこれによつて往動する。したがつて往動時は油
圧ポンプ２６により、復動時には逆止め２７のク
ラツキング圧力により往動側油室７に圧力が加わ
るので、第１可動シリンダ４は第２可動シリンダ
５に比して先に往動しかつ後に復動する。各可動
シリンダ４，５の復動時に往動側油室７に加える
べき背圧の大きさは、各可動シリンダ４，５の復
動側有効面積のばらつき、各摺動部分の摩擦抵抗
の相異、内部流路による圧力降下または往動側有
効面積の大きさ等の諸要因を考慮して決定されな
ければならない。逆止弁のクラツキング圧力は通
常数Kg／cm²であつてこれにより各可動シリンダの
動作順序が確保されるが、上述の諸要因によつて
は特に逆止弁２７を用いず、方向切換弁２３及び
配管抵抗による背圧のみによつても同様の効果を
得ることができる場合もある。 The directional switching valve 23 used here has 4 ports and 3 positions, but is not limited to this as long as it satisfies the above-mentioned functions. For example, it may be 5 ports with 3 positions, 4 ports with 2 positions, or 3 ports 2
Two positions may be used. Although a 2-port, 2-position on-off valve 30 is used, it may be a 3-port or 4-port valve. The hydraulic circuit shown in FIG. 2 may be connected by piping, or may be realized by stacking required modular valves on a base manifold. Generally, in order to stack modular valves, valves with the same diameter must be used for all of these valves, so if the on-off valve 3
If you try to cope with a large flow rate by increasing the diameter of the directional control valve 23 without using a 0, you will have to use large diameters for all other valves as well, which will result in a very expensive overall design. I get attached to things. Therefore, it can be said that the present invention is particularly effective when using a modular valve. Also check valve 2
7 ensures that a constant low back pressure is generated, but
This ensures the order of operation of each movable cylinder 4, 5 of the multi-stage double-acting cylinder 22. That is, when the piston 2 of the first movable cylinder 4 and the piston 3 of the second movable cylinder 5 are in a state separated from each other in the axial direction, the pressures in the reciprocating side oil chambers 12 and 13 of the first movable cylinder 4 are Since it works in the opposite direction for balance, if there is pressure in the oil chamber 7 on the forward side, this will cause forward movement. Therefore, pressure is applied to the forward-side oil chamber 7 by the hydraulic pump 26 during forward movement and by the cracking pressure of the non-return check 27 during backward movement, so that the first movable cylinder 4 is placed earlier than the second movable cylinder 5. It moves forward and returns later. The amount of back pressure that should be applied to the forward oil chamber 7 during the backward movement of each movable cylinder 4, 5 is determined by the variation in the effective area of the backward movement side of each movable cylinder 4, 5, and the relationship between the frictional resistance of each sliding part. It must be determined in consideration of various factors such as the pressure drop due to the internal flow path and the size of the effective area on the forward side. The cracking pressure of the check valve is normally several kg/ ^cm2 , which ensures the operating order of each movable cylinder, but depending on the factors mentioned above, the check valve 27 may not be used and the directional control valve may be used. In some cases, the same effect can be obtained by using only the back pressure caused by 23 and piping resistance.

上述のように構成した多段形複動油圧シリンダ
装置は、方向切換弁２３を切換えることによつて
多段形複動油圧シリンダ２２が往復動するととも
に、その速度は往動時は圧力補償付流量制御弁２
４ａによつて、復動時は圧力補償付流量制御弁２
４ｂによつて、それぞれ調整され、しかも各可動
シリンダ４，５の復動側有効面積を略同一として
いるから、各可動シリンダ４，５が順次切換わつ
て作動しても負荷の駆動速度はほぼ一定に保たれ
る。したがつて各可動シリンダの作動切換わり時
の衝撃を著しく軽減することができる。さらに、
開閉弁３０及び戻り流路３１の動きによつて往動
側油室７，８には背圧がほとんど発生せず、可動
シリンダ４，５の作動が円滑でほぼ一定の速度を
保つことができる。 In the multi-stage double-acting hydraulic cylinder device configured as described above, the multi-stage double-acting hydraulic cylinder 22 reciprocates by switching the directional control valve 23, and its speed is controlled by pressure-compensated flow rate control during forward movement. valve 2
4a, the pressure compensated flow control valve 2 is activated during double operation.
4b, and since the effective areas on the return side of each movable cylinder 4 and 5 are approximately the same, even if each movable cylinder 4 and 5 are sequentially switched and operated, the drive speed of the load is approximately the same. is kept constant. Therefore, the impact when switching the operation of each movable cylinder can be significantly reduced. moreover,
Due to the movement of the on-off valve 30 and the return passage 31, almost no back pressure is generated in the forward oil chambers 7, 8, and the movable cylinders 4, 5 can operate smoothly and maintain a substantially constant speed. .

以上のように本考案は、基本シリンダ内に、ピ
ストンをそれぞれ基端部側に有しそれぞれの復動
側油室の有効断面積を互に略同一とした複数の可
動シリンダを順次嵌装し、最小径の可動シリンダ
を除く可動シリンダの各ピストンに軸方向に流通
路を設けて各可動シリンダの往動側油室を相互に
連通させ、最小径の可動シリンダを除く可動シリ
ンダの各ピストンに軸方向の送通管及び半径方向
の流通路を設けて各可動シリンダの復動側油室を
相互に連通させてなる多段複動油圧シリンダを有
しており、上記往動側油室及び復動側油室をそれ
ぞれ油圧源または油タンクへ選択的に接続する方
向切換弁に接続し、上記復動側油室と上記方向切
換弁との間に、圧力補償付流量制御弁を介在接続
してなるので、多段形複動油圧シリンダの作動速
度をほぼ一定にできるとともに、各可動シリンダ
の作動切換わり時の衝撃を著しく軽減することが
できる。そして、開閉弁を有する戻り流路を形成
し、該開閉弁を上記多段形複動油圧シリンダが復
動するときのみ開とするようにしたので、復動方
向の出力低下を防止して一定の速度での作動をよ
り一層確実なものとすることができる。また、圧
力補償付流量制御弁を正逆各流れ方向の流量をそ
れぞれ別個に調整可能に接続すれば、往動及び復
動の各作動速度を別個に調整できかつ往復動共同
一速度とすることができる。また方向切換弁と油
タンクとの間に、逆止弁を油タンク方向に自由流
となるように介在接続することによつて、各可動
シリンダの動作順序が確保され、作動が安定す
る。 As described above, the present invention sequentially fits into a basic cylinder a plurality of movable cylinders each having a piston on the base end side and each having a reciprocating side oil chamber with substantially the same effective cross-sectional area. , a flow passage is provided in the axial direction in each piston of the movable cylinder except for the movable cylinder with the smallest diameter, so that the forward oil chambers of each movable cylinder are communicated with each other, and each piston of the movable cylinder except the movable cylinder with the smallest diameter is provided with a flow passage in the axial direction. It has a multi-stage double-acting hydraulic cylinder in which an axial passage pipe and a radial flow passage are provided to allow the reciprocating side oil chambers of each movable cylinder to communicate with each other, and the reciprocating side oil chambers and the reciprocating side oil chambers The movable side oil chambers are each connected to a directional control valve that selectively connects to a hydraulic power source or an oil tank, and a pressure-compensated flow control valve is interposed and connected between the double-movement side oil chamber and the directional control valve. Therefore, the operating speed of the multi-stage double-acting hydraulic cylinder can be kept almost constant, and the impact when switching the operation of each movable cylinder can be significantly reduced. In addition, a return flow path having an on-off valve is formed, and the on-off valve is opened only when the multi-stage double-acting hydraulic cylinder moves backward, thereby preventing a decrease in output in the backward movement direction and maintaining a constant level of output. The operation at high speed can be made even more reliable. In addition, by connecting a pressure-compensated flow control valve so that the flow rate in each of the forward and reverse flow directions can be adjusted separately, the forward and reverse operating speeds can be adjusted separately, and the reciprocating motion can be made to operate at the same speed. Can be done. Furthermore, by intervening and connecting a check valve between the directional control valve and the oil tank so as to allow a free flow toward the oil tank, the operating order of each movable cylinder is ensured and the operation is stabilized.

【図面の簡単な説明】[Brief explanation of the drawing]

図面は本考案の実施例であつて、第１図は多段
形複動油圧シリンダの断面図、第２図は油圧回路
図である。 １……基本シリンダ、２，３……ピストン、
４，５……可動シリンダ、６……流通路、７，８
……往動側油室、９……送通管、１０……流通
路、１２，１３……復動側油室、２２……多段形
複動油圧シリンダ、２３……方向切換弁、２４
ａ，２４ｂ……圧力補償付流量制御弁、２６……
油圧ポンプ（油圧源）、２７……逆止弁、２８…
…油タンク、３０……開閉弁、３１……戻り流
路。 The drawings show an embodiment of the present invention, in which FIG. 1 is a sectional view of a multi-stage double-acting hydraulic cylinder, and FIG. 2 is a hydraulic circuit diagram. 1... Basic cylinder, 2, 3... Piston,
4, 5...Movable cylinder, 6...Flow path, 7,8
...Forward side oil chamber, 9...Transmission pipe, 10...Flow passage, 12, 13...Return side oil chamber, 22...Multi-stage double-acting hydraulic cylinder, 23...Direction switching valve, 24
a, 24b...Flow control valve with pressure compensation, 26...
Hydraulic pump (hydraulic source), 27... Check valve, 28...
...Oil tank, 30...Opening/closing valve, 31...Return flow path.

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] 基本シリンダ内に、ピストンをそれぞれ基端部
側に有しそれぞれの復動側油室の有効断面積を互
に略同一とした複数の可動シリンダを順次嵌装
し、最小径の可動シリンダを除く可動シリンダの
各ピストンに軸方向に流通路を設けて各可動シリ
ンダの往動側油室を相互に連通させ、最小径の可
動シリンダを除く可動シリンダの各ピストンに軸
方向の送通管及び半径方向の流通路を設けて各可
動シリンダの複動側油室を相互に連通させてなる
多段形複動油圧シリンダを有しており、上記往動
側油室及び復動側油室をそれぞれ油圧源または油
タンクへ選択的に接続する方向切換弁に接続し、
上記復動側油室と上記方向切換弁との間に、圧力
補償付流量制御弁を介在接続するとともに、上記
往動側油室と上記油タンクとの間に開閉弁を有す
る戻り流路を形成し、該開閉弁を上記多段形複動
油圧シリンダが復動するときのみ開とするように
してなる多段形複動油圧シリンダ装置。 A plurality of movable cylinders each having a piston on the base end side and the effective cross-sectional area of each reciprocating side oil chamber being approximately the same are fitted in sequence into the basic cylinder, excluding the movable cylinder with the smallest diameter. An axial flow passage is provided in each piston of the movable cylinder to allow the forward oil chambers of each movable cylinder to communicate with each other, and an axial flow passage and a radius are provided in each piston of the movable cylinder except for the smallest diameter movable cylinder It has a multistage double-acting hydraulic cylinder in which the double-acting side oil chambers of each movable cylinder are communicated with each other by providing a flow path in the direction, and the forward-acting side oil chamber and the backward-acting side oil chamber are respectively connected to hydraulic pressure. connection to a directional valve that selectively connects to a source or oil tank;
A flow rate control valve with pressure compensation is interposed and connected between the backward-moving side oil chamber and the above-mentioned directional switching valve, and a return passage having an on-off valve is connected between the forward-moving side oil chamber and the oil tank. A multi-stage double-acting hydraulic cylinder device in which the on-off valve is opened only when the multi-stage double-acting hydraulic cylinder moves backward.